Some of my favorites that aren't on your list:
Hitman Reborn (long series, over 200 eps. Shonen Series about the mafia)
The Melancholy of Haruhi Suzumiya (28 eps. Based off a series of novels. Sci-fi.)
Yu Yu Hakusho (A little over 100 eps. Shonen series about demons and tournaments and stuff)
Tegami Bachi (50 eps. Shonen series about Letter Bees delivering Letters. One of the more unique anime I've seen recently.)
One Piece (I find it the better than the other big long running series.)
Bakuman (Made by the creators of Death Note. I haven't seen much of the anime, but the manga was great. About two kids growing up and trying to become Manga artists.)

You could check out Psycho-Pass, it's currently airing and written by the same guy who wrote the Fate/Zero novels. Very dark with a good amount of gore, and lots of fun. Another similar one that came out a few years ago is Phantom: Requiem for the Phantom, also written by the same guy. (He's also the one who wrote Madoka, always very dark stories)

Another recommendation for Haruhi, as well. Especially the movie, it's very good.

And keep an eye out for Nekomonogatari Kuro that just aired a couple nights ago, since you liked the Monogatari series. It takes place before Bakemonogatari.

A good tip for most of you is to make a profile on anime-planet.com or myanimelist.net
Helps you keep track of all the anime series you have watched, are watching, want to watch and so on. It is also a list there of most of the anime that exist (with a star ranking system on anime-planet at least).

Also surprised that so few recommend code geass. It is one of the best anime out there imo. :P

That's what I said when I was watching it! I think when I was watching, however, the series wasn't complete yet (it was either Steins or Mirai Nikki). I could NOT stop watching it however. Great series, totally recommend it.

Eiken is a deconstruction of the ecchi genre, it has a very deep plot and catches you off guard out of no where. I highly recommend this to anyone who hasn't seen it yet, you will be pleasantly surprised.